Brought our camper home and now I can't keep fuses in it on one circuit. The camper is a 2014 HW31SCTH. The fuse is a 15 amp that runs the two outside lights, the radio, the water heater, furnace and gas detector. I can replace the fuse and run everything on that circuit just fine for a couple hours...Then all of the sudden it pops. Any idea where I look first?

First you need to know if that is the proper size fuse for the circuit You also need to see the voltage output of your battery if your battery is low it will take much more current to run your furnace. then you need to see that all items are off, then operate only one item at a time to see if it is a specifique item that is causing the problem or when you use multiple items at a time. I Would suspect the furnance is the problem do to the fact it has an electric motor for the blower which usualy draws a lot of current on start-up.

The fuse is (was) the original one from the factory, and is labeled 15 amp on the panel. The fuse blows whether on battery power or the converter, and both have been checked for proper voltage. The furnace has a separate fusable link that is a 7.5amp fuse. That fuse has not blown. The only things on when it blows are the detector and the radio. I'm going to disconnect everything, make sure the fuse doesn't blow with nothing on it (if it does I have a converter problem right?) then add things one by one and give it a few days in between to make sure each item doesn't blow it.

Well, I got an automotive circuit tester today. You plug a fuse into it and plug it into the circuit and it tells you the amperage draw on that particular circuit.
Long story short, I had everything turned off or disconnected on that circuit and the tester said it was still drawing between 18 and 22 amps! That was battery connected, disconnected, whatever. Same readings every time. I tried the tester in another circuit to be sure it worked, and it does. Put a 15 amp fuse back in that first circuit and it still popped em.

When I had the tester up and it was at 22 amps, I had to have a 30 amp fuse in it to keep it from blowing right away. I only 'tested' for a few seconds so as not to heat up wiring or connections. However, when that circuit was on the converter was making a strange groaning noise. And this time I was never able to get it to run at all, it just popped fuses as soon as I turned it on.

So do I have a bad converter? Do you think I should take things a step further and disconnect the wire to that circuit behind the converter? That would mean taking the box apart, but if that's the only way to get warranty replacement I can certainly do that...remember that this is a 2014 so it is indeed under warranty...

Some multimeter have 20amp meter you just need to place the meter in the write setting and use the probes in the place of the fuse the red lead on power side and the black on the load side veyfie first that the meter is fused an your lead are in the write position.